• Mesabi Nugget Plant, Hoyt Lakes, Minnesota, November 2009

    Mesabi Nugget

    Overview

    On the Mesabi Iron Range in the untamed country of northeastern Minnesota, Steel Dynamics has purchased more than 6,000 acres bearing rich deposits of taconite. These iron deposits are to be mined and then the iron extracted will be converted to iron nuggets. The nuggets are used as a feedstock to the electric-arc furnaces of SDI’s Midwest steel mills.

    Nugget-making employs new technology developed by Kobe Steel for the direct reduction of iron. This ITmk3® process is energy efficient, environmentally friendlier than other ironmaking technologies, and yields high quality iron nuggets for steelmaking.

    Background information
    December 2009 article
    News Release: Steel Dynamics Announces First Production of Mesabi Nuggets – January 13, 2010

    ITmk3® is a registered trademark of Kobe Steel, Ltd.


  • Mesabi Nugget Plant at start-up, December 2009

    Mesabi Nugget

    The Nugget Plant

    The Mesabi Nugget plant at Hoyt Lakes, Minnesota, is the first of its kind in the world–the first commercial iron-making plant to use the ITmk3 process.

    The fully integrated and self-contained facility converts powdery raw materials into solid, elliptically shaped iron nuggets about one-half inch in diameter.

    These 98-percent-pure iron nuggets are ideal for use in steelmaking, and are used as a substitute for imported pig iron.

    The first nugget plant, with a rated capacity of 500,000 metric tons of nuggets per year, started up in December 2009. Its first shipment of nuggets for testing in SDI’s steel mills was made in February 2010.

    Background information
    December 2009 article
    News Release: Steel Dynamics Announces First Production of Mesabi Nuggets – January 13, 2010

  • Mesabi Nugget

    Production Process

    Nugget production begins with the preparation of raw materials: pulverized coal, iron concentrate, and other needed materials. These are mixed and aglomerated into marble-sized balls. The balls are dried and then fed into a rotary hearth furnace, where they are heated to near melting and then are rapidly cooled. At this point, iron nuggets are formed and they disassociate from other materials called slag.

    Production of one tonne (metric ton) of iron nuggets requires about 1.45 tonnes of iron concentrate, 0.34 tonnes of reductant coal, and 0.12 tonnes of anthracite coal. Until SDI’s iron mining and concentrating operations can begin at the Mesabi site, iron concentrate is purchased. Coal is delivered by rail from Appalachian sources.

    The Process
    December 2009 article
    Technical Paper presented at AISTech 2009

  • Mesabi Nugget

    The Future

    During 2010 the Mesabi Nugget facility made excellent progress in ramping up production of nuggets. Process refinements are ongoing as more is learned about the process in full-scale production.

    As production volume grows, rail shipments of iron nuggets to SDI’s Flat Roll mill are increasing.

    Meanwhile, Steel Dynamics seeks to obtain the needed mining permits from the State of Minnesota to reopen the former LTV iron mine we purchased. We expect it to take less than a year to prepare for mining after issuance of the permit.  

    Once the process has proven itself technically and economically, and the mining permits are in place, Steel Dynamics would consider constructing, alone or with partners, up to three additional nugget production modules of similar size at the Hoyt Lakes site.

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